<template>
  <scroll :probe-type="3" class="index-list" @scroll="onScroll" ref="scrollRef">
    <ul ref="groupRef">
      <li v-for="group in data" :key="group.title" class="group">
        <h2 class="title">{{ group.title }}</h2>
        <ul>
          <li v-for="item in group.list" :key="item.id" class="item" @click="onItemClick(item)">
            <img class="avatar" v-lazy="item.pic">
            <span class="name">{{ item.name }}</span>
          </li>
        </ul>
      </li>
    </ul>
    <div class="fixed" v-show="fixedTitle" :style="fixStyle">
      <div class="fixed-title">{{ fixedTitle }}</div>
    </div>
    <div class="shortcut" @touchstart.stop.prevent="onShortcutTouchStart" @touchmove.stop.prevent="onShortcutTouchMove"
      @touchend.stop.prevent="onShortcutTouchEnd">
      <ul>
        <!-- data-xxxx js通过 dataset.xxxx 获取设置的值 -->
        <li v-for="(item, index) in shortcutList" :key="item" class="item" :data-index="index"
          :class="{ 'current': currentIndex === index }">
          {{ item }}
        </li>
      </ul>
    </div>
  </scroll>
</template>

<script>
import Scroll from '@/components/base/scroll/scroll'
import useFixed from './use-fixed'
import useShortcut from './use-shortcut'
export default {
  name: 'index-list',
  props: {
    data: {
      type: Array,
      default() {
        return []
      }
    }
  },
  components: {
    Scroll,
  },
  emit: ['select'],
  setup(props, {emit}) {
    const { groupRef, onScroll, fixedTitle, fixStyle, currentIndex } = useFixed(props)
    const {
      shortcutList,
      onShortcutTouchStart,
      onShortcutTouchMove,
      onShortcutTouchEnd,
      scrollRef
    } = useShortcut(props, groupRef)

    function onItemClick (item) {
      emit('select', item)
    }

    return {
      groupRef,
      onScroll,
      fixedTitle,
      fixStyle,
      currentIndex,
      shortcutList,
      scrollRef,
      onShortcutTouchStart,
      onShortcutTouchMove,
      onShortcutTouchEnd,
      onItemClick
    }
  }
}
</script>

<style lang="scss" scoped>
.index-list {
  position: relative;
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: $color-background;

  .group {
    padding-bottom: 30px;

    .title {
      height: 30px;
      line-height: 30px;
      padding-left: 20px;
      font-size: $font-size-small;
      color: $color-text-l;
      background: $color-highlight-background;
    }

    .item {
      display: flex;
      align-items: center;
      padding: 20px 0 0 30px;

      .avatar {
        width: 50px;
        height: 50px;
        border-radius: 50%;

        .name {
          margin-left: 20px;
          color: $color-text-l;
          font-size: $font-size-medium;
        }
      }
    }
  }

  .fixed {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;

    .fixed-title {
      height: 30px;
      line-height: 30px;
      padding-left: 20px;
      font-size: $font-size-small;
      color: $color-text-l;
      background: $color-highlight-background;
    }
  }

  .shortcut {
    position: absolute;
    right: 4px;
    top: 50%;
    transform: translateY(-50%);
    width: 20px;
    padding: 20px 0;
    border-radius: 10px;
    text-align: center;
    background: $color-background-d;
    font-family: Arial, Helvetica, sans-serif;

    .item {
      padding: 3px;
      line-height: 1;
      color: $color-text-l;
      font-size: $font-size-small;

      &.current {
        color: $color-theme;
      }
    }
  }
}
</style>